Brassinosteroid accelerates the growth of Psidium hybrid during acclimatization of seedlings obtained from minicuttings

ABSTRACT Guava rootstocks can be multiplied by minicuttings in environment with a high relative humidity, being necessary an acclimatization period. Certain growth regulators favor the acclimatization, with brassinosteroids being successfully used in other fruit plants. This study aimed to shorten the multiplication time of the BRS Guaraçá hybrid by applying Biobras-16 (BB-16) during the acclimatization of seedlings obtained from minicuttings. The treatments consisted of five BB-16 concentrations (0, 0.1, 0.3, 0.5 and 1.0 mg L-1), applied in a randomized block design, in a split-plot arrangement, with four replications and five seedlings per plot, repeated at two seasons: winter and spring/summer. After 60 days of acclimatization, shoot and root growth indicators increased as a function of the BB-16 application, particularly at concentrations between 0.3 and 0.6 mg L-1. The brassinosteroid can be used to stimulate the growth of BRS Guaraçá seedlings obtained from minicuttings, shortening its production time and improving its seedling quality.

摘要 番石榴砧木可在高相对湿度环境下通过微型插穗进行繁殖，且需经过驯化阶段。部分生长调节剂可促进驯化过程，其中油菜素甾醇（brassinosteroids）已在其他果树作物中成功应用。本研究旨在通过在微型插穗来源幼苗的驯化阶段施加Biobras-16（BB-16），缩短BRS Guaraçá杂交品种的繁殖周期。试验设置5个BB-16浓度梯度（0、0.1、0.3、0.5及1.0 mg·L⁻¹），采用随机区组裂区设计，设置4次重复，每小区种植5株幼苗，试验分别在冬季以及春夏季两个季节开展重复。驯化60天后，植株地上部与根系的生长指标随BB-16施加浓度升高而提升，尤其在0.3~0.6 mg·L⁻¹浓度区间效果最为显著。综上，油菜素甾醇可用于促进微型插穗来源的BRS Guaraçá幼苗生长，缩短其繁育周期并提升幼苗品质。